a-a a-b a-c a-z aaa aab aac aam aao aaz ab- aba abb abc abm abo abz ac- aca acb acc acm aco acz ama amb amc amm amo amz aoa aob aoc aom aoo az- aza azb azm azo azz baa bab bac bam bao baz bba bbb bbc bbm bbo bca bcb bcc bcm bco bcz bma bmb bmc bmm bmo bmz boa bob boc bom boo boz bza bzo bzz c-- caa cab cac cam cao caz cba cbb cbc cbm cbo cbz cca ccb ccc ccm cco ccz cma cmb cmc cmm cmo co- coa cob coc com coo coz cz- czc czm czo m-o maa mab mac mam mao maz mba mbb mbc mbm mbo mc- mca mcb mcc mcm mco mcz mma mmb mmc mmm mmo mmz moa mob moc mom moo moz mza mzb mzm oaa oab oac oam oao ob- oba obb obc obm obo oc- oca ocb occ ocm oco ocz om- oma omb omc omm omo omz oo- ooa oob ooc oom ooo oza ozm ozo ozz zaa zab zac zam zao zaz zbb zbc zbm zco zma zmb zmc zmm zo- zoa zob zoc zom zoo zzz